Daniela Hossu

Evolved Fuzzy Control System for a Steam Generator

Poor control of steam generator water level is the main cause of unexpected shutdowns in nuclear power plants. Particularly at low powers, it is a difficult task due to shrink and swell phenomena and flow measurement errors. In addition, the steam generator is a highly complex, nonlinear and time-varying system and its parameters vary with operating conditions. Therefore, there is a need to systematically investigate the problem of controlling the water level in the steam generator in order to prevent such costly reactor shutdowns. The objective of this paper is to design, evaluate and implement a water level controller for steam generators based on a fuzzy model predictive control approach. An original concept of modular evolved control system, seamless and with gradual integration into the existent control system is proposed as base of implementation of the presented system.

Advanced control strategies for irrigation systems

Water management and irrigation scheduling have become the main subjects of different studies in the last decades, due to their high influence on crop performance indicators. This study presents the most important parameters that have to be monitored in an irrigation management system and the most important ones are synthesized: air moisture and temperature, soil air and moisture, evapotranspiration. Based on the monitoring of these parameters, different control strategies and methods can be applied for optimization and efficiency of irrigation systems. The synthesis in this paper starts with classical control systems and, also, advanced methods such as fuzzy concept, decision support systems and model predictive control. Considering the currently necessity of integration into the Cyber-Physical Systems (CPS) concept, the paper finally proposes an irrigation control system for vineyards. The SCADA architecture is suitable for the Romanian context, it allows flexibility and ease of use and it reduced both energy consumption and irrigation operation costs.

Complex networks to model the economic globalization process

Abstract The paper analyses the effects of the process of globalization not only in economic terms, but rather the profound change in the structural properties of the socio-economic networks towards more complexity (more connectivity, more interactions, faster changes and greater uncertainties). We apply network metrics to international trade data and show a clear trend towards a rise of complexity in the patterns of global economic exchanges. We suggest that the observed increase in scale and connectivity of the common economic networks induces greater uncertainties and risks of large-scale instabilities and propose some efficient means to manage network complexity based on efficient models.